1. Technical Field
The present invention relates to lubricants suitable for plastic processing of steel and other metal materials.
2. Related Art
European Patent Publication No. 0 947 519 discloses water-based lubricants that contain sulfur as a coordinating atom. Such lubricants preferably comprise a metal chelate compound that is dispersed or suspended in water or another aqueous solution and such lubricants also preferably contain no oil. A lubricating film is formed on a metal surface when the metal chelate compound is applied to the metal surface. Because the lubricating film contains sulfur as a coordinating atom, sulfur radials may be generated via a tribo-chemical reaction when the metal is subjected to a high pressure, such as the high pressures generated during plastic processing of the metal. The sulfur radials are highly reactive and rapidly form metal sulfides on the metal surface, which provides a lubricating effect when the metal is worked or processed.